1. Field of the Invention
This invention relates to a scanner with an optical-electric module (O/E), an incoherent fiber bundle, and a scanner head connected to the O/E module by the incoherent fiber bundle. More particularly, the scanner according to the invention includes, in one embodiment, illumination fibers carrying only illumination light from the O/E module to the scanner head, and pickup fibers carrying only sensed light from the said scanner head to the O/E module.
2. Related Art
A scanner is a device, which is useful for picking up images in a form readable by computers. Although desktop scanners are useful for picking up images, they are impractical for use with portable computers. Hand-held scanners have been developed to fulfill the need for portable computer users to scan images.
Hand-held scanners must ideally be easy to use, easy to install, lightweight, sturdy, rugged, accurate, reliable, and inexpensive. One design for a hand-held scanner is the pen-shaped design. In this design, the scanner is roughly the shape of a pen. This type of hand-held scanner is dragged across a pickup area on its side. The image in the pickup area is picked up, or sensed, and is provided to the computer.
One example of a pen-shaped hand-held optical fiber scanner is reported in "Compact Imaging Apparatus for a Pen-Shaped Hand-Held Scanner", Proceedings of the SPIE, Int'l Society for Optical Engineering, Vol. 3019, pp. 168-173, February 1997. One drawback of this design of scanner is that electrical components are included in the scanner head (i.e., the pen). Because the scanner head is hand-held, it is subject to being dropped and jarred.
To improve the resistance of a hand-held scanner to being dropped and jarred, different approaches are possible. One excellent approach is to remove the electronic components from the scanner head as in patent application Ser. No. 09/124,832, mentioned above.
According to this approach, a scanner has an O/E module connected to a scanning head by an incoherent fiber bundle. The scanning head is all-optical, and is free of electronic components. The O/E module introduces source RGB light into the fibers, and also permits the sensed light to be provided to a CCD. The fibers in the incoherent fiber bundle are unidirectional in that they either carry illumination light from the O/E to the scanner head or sensed light from the scanner head to the O/E module. The O/E module is the module of the scanner with the electronic elements. Because the electronic components are on the O/E module, separate from the scanner head, the scanner head is lighter in weight and less susceptible to damage from being dropped or jarred. Moreover, the O/E module may be miniaturized and integrated into a computer motherboard or a PC card device meeting, e.g., the Personal Computer Memory Card International Association (PCMCIA) standard.
The scanner according to application Ser. No. 09/124,832 provides that the RGB light enters the fibers of the incoherent fiber bundle using a side-coupling approach in the O/E module. That is, the RGB source light is fed into a linear light guide, such as a fiber, which is coupled to the fibers in the incoherent fiber bundle in the O/E module. More particularly, the RGB light is coupled into a fiber of the incoherent fiber bundle through a notch which is made in the fiber.
One shortcoming of the side-coupling approach in the foregoing scanner is that a notch must be made in the fibers of the incoherent fiber bundle so as to couple them with the source light. The making of this notch is not a trivial task, and it would be an important improvement to provide a hand-held pen-shaped scanner with all of the advantages of the scanner just described, but without the drawback of a physical alteration to the fibers.